update spotlight code (Harry Tuttle)

Src/Graphics/New3D/New3D.cpp

@@ -801,10 +801,6 @@ void CNew3D::RenderViewport(UINT32 addr)
 		vp->spotRange[0] = 1.0f / (*(float *)&vpnode[0x21]);							// spotlight start
 		vp->spotRange[1] = *(float *)&vpnode[0x1F];										// spotlight extent
 
-		// Star Wars Trilogy needs this
-		vp->spotRange[0] = std::min(vp->spotRange[0], std::numeric_limits<float>::max());
-		vp->spotRange[0] = std::max(vp->spotRange[0], std::numeric_limits<float>::lowest());
-
 		vp->spotColor[0] = color[spotColorIdx][0];										// spotlight color
 		vp->spotColor[1] = color[spotColorIdx][1];
 		vp->spotColor[2] = color[spotColorIdx][2];

Src/Graphics/New3D/R3DShader.cpp

@@ -164,12 +164,40 @@ void main()
 	float ellipse;
 	ellipse = length((gl_FragCoord.xy - spotEllipse.xy) / spotEllipse.zw);
 	ellipse = pow(ellipse, 2.0);  // decay rate = square of distance from center
-	ellipse = 1.0 - ellipse;      // invert
-	ellipse = max(0.0, ellipse);  // clamp
-
-	if (lightEnabled) {
-		vec3   lightIntensity;
-		vec3   sunVector;     // sun lighting vector (as reflecting away from vertex)
+	ellipse = 1.0 - ellipse;      // invert
+	ellipse = max(0.0, ellipse);  // clamp
+
+	// Compute spotlight and apply lighting
+	float enable, absExtent, d, inv_r, range;
+
+	// start of spotlight
+	enable = step(spotRange.x, -fsViewVertex.z);
+
+	if (spotRange.y == 0.0) {
+		range = 0.0;
+	}
+	else {
+		absExtent = abs(spotRange.y);
+
+		d = spotRange.x + absExtent + fsViewVertex.z;
+		d = min(d, 0.0);
+
+		// slope of decay function
+		inv_r = 1.0 / (1.0 + absExtent);
+
+		// inverse-linear falloff
+		// Reference: https://imdoingitwrong.wordpress.com/2011/01/31/light-attenuation/
+		// y = 1 / (d/r + 1)^2
+		range = 1.0 / pow(d * inv_r - 1.0, 2.0);
+		range *= enable;
+	}
+
+	float lobeEffect = range * ellipse;
+	float lobeFogEffect = enable * ellipse;
+
+	if (lightEnabled) {
+		vec3   lightIntensity;
+		vec3   sunVector;     // sun lighting vector (as reflecting away from vertex)
 		float  sunFactor;     // sun light projection along vertex normal (0.0 to 1.0)
 
 		// Sun angle
@@ -196,28 +224,12 @@ void main()
 
 		// Upper clamp is optional, step 1.5+ games will drive brightness beyond 100%
 		if(intensityClamp) {
-			lightIntensity = min(lightIntensity,1.0);
-		}
-
-		// Compute spotlight and apply lighting
-		float enable, range, d;
-		float inv_r = 1.0 / spotEllipse.z; // slope of decay function
-
-		d = spotRange.x + spotRange.y + fsViewVertex.z;
-		enable = step(spotRange.x + min(spotRange.y, 0.0), -fsViewVertex.z);
-
-		// inverse-linear falloff
-		// Reference: https://imdoingitwrong.wordpress.com/2011/01/31/light-attenuation/
-		// y = 1 / (d/r + 1)^2
-		range = 1.0 / pow(min(0.0, d * inv_r) - 1.0, 2.0);
-		range = clamp(range, 0.0, 1.0);
-		range *= enable;
-
-		float lobeEffect = range * ellipse;
-
-		lightIntensity.rgb += spotColor*lobeEffect;
-
-		finalData.rgb *= lightIntensity;
+			lightIntensity = min(lightIntensity,1.0);
+		}
+
+		lightIntensity.rgb += spotColor*lobeEffect;
+
+		finalData.rgb *= lightIntensity;
 
 		// for now assume fixed shading doesn't work with specular
 		if (specularEnabled && !fixedShading) {
@@ -250,16 +262,16 @@ void main()
 	}
 
 	// Final clamp: we need it for proper shading in dimmed light and dark ambients
-	finalData.rgb = min(finalData.rgb, vec3(1.0));
-
-	// Spotlight on fog
-	vec3 lSpotFogColor = spotFogColor * ellipse * fogColour.rgb;
-
-	 // Fog & spotlight applied
-	finalData.rgb = mix(finalData.rgb, lSpotFogColor * fogAttenuation + fogData.rgb, fogData.a);
-
-	gl_FragColor = finalData;
-}
+	finalData.rgb = min(finalData.rgb, vec3(1.0));
+
+	// Spotlight on fog
+	vec3 lSpotFogColor = spotFogColor * fogAttenuation * fogColour.rgb * lobeFogEffect;
+
+	 // Fog & spotlight applied
+	finalData.rgb = mix(finalData.rgb, fogData.rgb + lSpotFogColor, fogData.a);
+
+	gl_FragColor = finalData;
+}
 )glsl";
 
 R3DShader::R3DShader(const Util::Config::Node &config)